/* ================================================================
   problems.css - Verifiable Problems section styles
   Loaded alongside the site's global styles.css
   ================================================================ */

/* ===== Hero ===== */
.problems-hero {
    padding: calc(var(--nav-height) + var(--space-16)) var(--content-padding) var(--space-8);
    max-width: var(--content-width);
    margin: 0 auto;
}

.problems-hero .eyebrow {
    text-align: left;
    margin-bottom: var(--space-3);
    text-transform: none;
}

.problems-cta {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-4) var(--content-padding) var(--space-8);
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.problems-cta p {
    margin-bottom: var(--space-2);
}

.problems-cta a {
    color: var(--accent);
    text-decoration: underline;
    text-underline-offset: 2px;
}

.problems-cta a:hover {
    color: var(--accent-hover);
}

.problems-hero h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    margin-bottom: var(--space-4);
    line-height: 1.15;
}

.problems-hero__subtitle {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    margin-bottom: 0;
    line-height: 1.6;
}

.badge-row {
    display: flex;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background-color: var(--bg-secondary);
}

.badge svg {
    width: 13px;
    height: 13px;
    opacity: 0.7;
    flex-shrink: 0;
}

/* ===== State views ===== */
.loading-state {
    text-align: center;
    padding: var(--space-16);
    color: var(--text-tertiary);
    font-size: var(--text-sm);
}

.error-state {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-6) var(--content-padding);
    background-color: var(--bg-secondary);
    border-left: 4px solid #dc2626;
    border-radius: 0 8px 8px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ===== Problem index (card list) ===== */
.problems-index {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--content-padding) var(--space-4);
}

.problem-card-link {
    display: block;
    text-decoration: none;
    color: inherit;
    margin-bottom: var(--space-4);
}

.problem-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: var(--space-6) var(--space-8);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-6);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.problem-card-link:hover .problem-card {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow);
}

.problem-card__left h3 {
    margin: 0 0 var(--space-2);
    font-size: var(--text-xl);
}

.problem-card__left p {
    margin: var(--space-2) 0 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.problem-card__meta {
    display: flex;
    gap: var(--space-2);
    flex-wrap: wrap;
    align-items: center;
    margin-bottom: var(--space-2);
}

.problem-card__right {
    flex-shrink: 0;
    color: var(--text-tertiary);
}

.problem-card__right svg {
    width: 20px;
    height: 20px;
}

/* ===== Tags ===== */
.tag {
    display: inline-flex;
    align-items: center;
    padding: 3px 10px;
    border-radius: 4px;
    font-size: 0.78rem;
    font-weight: 500;
    line-height: 1.6;
}

.tag--domain {
    background-color: var(--accent-light);
    color: var(--accent);
}

.tag--open {
    background-color: var(--accent-light);
    color: var(--accent);
}

[data-theme="dark"] .tag--open {
    color: var(--accent-hover);
}

.tag--star {
    background-color: var(--accent);
    color: #fff;
    font-size: 0.72rem;
    padding: 2px 7px;
}

[data-theme="dark"] .tag--star {
    color: #000;
}

/* ===== Problem detail view ===== */
.problem-detail {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: calc(var(--nav-height) + var(--space-8)) var(--content-padding) var(--space-4);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    text-decoration: none;
    margin-bottom: var(--space-8);
    transition: color 0.2s;
}

.back-link:hover {
    color: var(--text-primary);
}

.back-link svg {
    width: 16px;
    height: 16px;
}

.problem-header {
    margin-bottom: var(--space-2);
}

.problem-header h2 {
    border-bottom: none;
    padding-bottom: 0;
    margin-top: 0;
    margin-bottom: 0;
    font-size: var(--text-3xl);
    line-height: 1.2;
}

/* ===== Attribution block ===== */
.attribution-block {
    margin-bottom: var(--space-4);
    padding: var(--space-2) 0;
}

.attribution-row {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
    padding: var(--space-2) 0;
}

.attribution-people {
    display: flex;
    gap: var(--space-4);
    flex-wrap: wrap;
}

.attribution-card {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.attribution-card__photo {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    object-fit: cover;
    border: 1px solid var(--border);
}

.attribution-card__info {
    display: flex;
    flex-direction: column;
}

.attribution-card__name {
    font-size: var(--text-base);
    font-weight: 600;
    color: var(--text-primary);
}

.attribution-card__institution {
    font-size: 0.75rem;
    color: var(--text-secondary);
    display: inline;
}

.attribution-card__social {
    display: inline-flex;
    gap: var(--space-2);
    margin-left: var(--space-2);
    vertical-align: middle;
}

.attribution-card__social a {
    color: var(--text-tertiary);
    transition: color 0.2s ease;
}

.attribution-card__social a:hover {
    color: var(--accent);
}

.attribution-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--accent);
    letter-spacing: 0.05em;
    min-width: 100px;
    flex-shrink: 0;
}

.attribution-names {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.problem-description {
    font-size: var(--text-base);
    color: var(--text-secondary);
    margin-bottom: var(--space-6);
    line-height: 1.7;
    max-width: 760px;
}

.context-box {
    background-color: var(--bg-secondary);
    border-left: 4px solid var(--accent);
    border-radius: 0 8px 8px 0;
    padding: var(--space-4) var(--space-6);
    margin-bottom: var(--space-8);
}

.context-box p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.75;
}

/* ===== Leaderboard ===== */
.leaderboard-section {
    margin-bottom: var(--space-12);
}

.leaderboard-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
}

.leaderboard-header h3 {
    margin: 0;
    font-size: var(--text-xl);
}

.leaderboard-note {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    font-style: italic;
}

.table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: 10px;
}

table.leaderboard {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

table.leaderboard thead {
    background-color: var(--bg-secondary);
}

table.leaderboard th {
    padding: 12px 16px;
    text-align: left;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-tertiary);
    white-space: nowrap;
    border-bottom: 1px solid var(--border);
}

table.leaderboard td {
    padding: 11px 16px;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

table.leaderboard tbody tr:last-child td {
    border-bottom: none;
}

table.leaderboard tbody tr:hover {
    background-color: var(--bg-secondary);
}

/* (row-highlight removed; notes now shown as inline text) */

/* column widths + fonts */
.td-n {
    font-weight: 700;
    font-size: 1rem;
    color: var(--text-primary);
    min-width: 70px;
}

.n-label {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    white-space: nowrap;
}

.td-mod {
    color: var(--text-tertiary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    width: 70px;
}

.td-best {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    color: var(--text-primary);
    white-space: nowrap;
}

.td-pct {
    width: 190px;
}

.pct-cell {
    display: flex;
    align-items: center;
    gap: 10px;
}

.pct-bar-track {
    flex: 1;
    height: 6px;
    background-color: var(--bg-tertiary);
    border-radius: 3px;
    overflow: hidden;
    min-width: 60px;
}

.pct-bar-fill {
    height: 100%;
    border-radius: 3px;
    background-color: var(--accent);
}

.pct-value {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    white-space: nowrap;
    min-width: 44px;
    text-align: right;
}

.pct-unknown {
    font-size: 0.82rem;
    color: var(--text-tertiary);
}

.td-status {
    width: 90px;
}

.status-open {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 3px 9px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    background-color: var(--accent-light);
    color: var(--accent);
    white-space: nowrap;
}

[data-theme="dark"] .status-open {
    color: var(--accent-hover);
}

.status-solved {
    display: inline-flex;
    align-items: center;
    padding: 3px 9px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    white-space: nowrap;
}

.status-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background-color: var(--accent);
    flex-shrink: 0;
}

.leaderboard-footer-note {
    margin-top: var(--space-3);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.section-block h3 {
    margin-top: 0;
    margin-bottom: var(--space-4);
    font-size: var(--text-lg);
}

/* ===== Code block ===== */
.code-block {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-4) var(--space-5);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.82rem;
    line-height: 1.7;
    color: var(--text-primary);
    overflow-x: auto;
    white-space: pre;
    margin-bottom: var(--space-4);
}

.tok-key  { color: var(--accent); }
.tok-num  { color: #7c3aed; }
.tok-punc { color: var(--text-tertiary); }
.tok-ellip { color: var(--text-tertiary); font-style: italic; }

[data-theme="dark"] .tok-num { color: #a78bfa; }

/* ===== Numbered steps ===== */
.steps {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: steps;
}

.steps li {
    counter-increment: steps;
    display: flex;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
    align-items: flex-start;
}

.steps li::before {
    content: counter(steps);
    flex-shrink: 0;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background-color: var(--accent-light);
    color: var(--accent);
    font-size: 0.75rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 2px;
}

[data-theme="dark"] .steps li::before {
    color: var(--accent-hover);
}

.steps li p {
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.steps li strong {
    color: var(--text-primary);
}

/* ===== Accordion ===== */
details.accordion {
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-bottom: var(--space-4);
}

details.accordion summary {
    padding: var(--space-4) var(--space-6);
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: var(--text-primary);
    user-select: none;
}

details.accordion summary::-webkit-details-marker { display: none; }

details.accordion summary::after {
    content: "+";
    font-size: 1.2rem;
    color: var(--text-tertiary);
}

details.accordion[open] summary::after {
    content: "−";
}

details.accordion .accordion-body {
    padding: var(--space-4) var(--space-6) var(--space-5);
    border-top: 1px solid var(--border);
}

/* bounds table inside accordion */
.bounds-list {
    list-style: none;
    padding: 0;
    margin: var(--space-4) 0 0;
}

.bounds-list li {
    padding: var(--space-3) var(--space-2);
    border-bottom: 1px solid var(--border);
    display: grid;
    grid-template-columns: 170px 1fr;
    gap: var(--space-4);
    font-size: 0.875rem;
    margin: 0;
}

.bounds-list li:last-child {
    border-bottom: none;
}

.bounds-list .mod-key {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: var(--accent);
    font-weight: 600;
}

.bounds-list .bound-detail {
    color: var(--text-secondary);
}

.bound-name {
    font-weight: 600;
    color: var(--text-primary);
}

/* references list inside accordion */
.refs-list {
    list-style: none;
    padding: 0;
    margin: var(--space-4) 0 0;
}

.refs-list li {
    padding: var(--space-3) var(--space-2);
    border-bottom: 1px solid var(--border);
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.refs-list li:last-child {
    border-bottom: none;
}

/* ===== Verify note ===== */
.verify-note {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: var(--space-4) var(--space-5);
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--space-4);
}

.verify-note svg {
    flex-shrink: 0;
    color: var(--accent);
    margin-top: 2px;
}

/* ===== Warmup block ===== */
.warmup-block {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: var(--space-5) var(--space-6);
    margin-bottom: var(--space-8);
}

.warmup-block h3 {
    margin-top: 0;
    margin-bottom: var(--space-3);
    font-size: var(--text-lg);
}

/* ===== Game of Life Widget ===== */
.gol-widget {
    text-align: center;
}

.gol-widget h3 {
    text-align: left;
}

.gol-widget p {
    text-align: left;
}

.gol-widget canvas {
    border: 1px solid var(--border);
    border-radius: 6px;
    cursor: crosshair;
    display: block;
    margin: 0 auto var(--space-4);
}

.gol-controls {
    display: flex;
    gap: var(--space-3);
    justify-content: center;
    flex-wrap: wrap;
}

.gol-btn {
    padding: 6px 16px;
    border-radius: 6px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background-color: var(--bg-secondary);
    cursor: pointer;
    transition: background-color 0.15s, border-color 0.15s;
}

.gol-btn:hover {
    background-color: var(--bg-tertiary);
}

.gol-btn--active {
    border-color: var(--accent);
    color: var(--accent);
}

.gol-status {
    margin-top: var(--space-3);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

/* ===== Section divider (legacy, not used in card layout) ===== */
.section-divider {
    border: none;
    border-top: 1px solid var(--border);
    margin: var(--space-10) 0;
}

/* Remove margin from last child inside section cards */
.section-card > *:last-child {
    margin-bottom: 0;
}

/* ===== Active nav link ===== */
.header-link--active {
    color: var(--text-primary) !important;
    font-weight: 600;
}

/* ===== Submit CTA ===== */
.btn--disabled {
    display: inline-flex;
    align-items: center;
    padding: 10px 22px;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid var(--border);
    color: var(--text-tertiary);
    background-color: var(--bg-secondary);
    cursor: not-allowed;
    opacity: 0.7;
    white-space: nowrap;
}

.btn--disabled svg {
    margin-right: 6px;
    flex-shrink: 0;
}

/* ===== Section cards ===== */
.section-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: var(--space-8);
    margin-bottom: var(--space-6);
}

.section-card__title {
    font-size: var(--text-2xl);
    margin-top: 0;
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-4);
    border-bottom: 2px solid var(--accent);
    color: var(--text-primary);
}

/* Sub-headings inside cards */
.section-card .section-block h3,
.section-card .scoring-block h3,
.section-card .references-section h3,
.section-card .cite-block h3,
.section-card .leaderboard-header h3 {
    font-size: var(--text-lg);
    color: var(--text-primary);
    margin-top: 0;
}

.section-card .context-box h3 {
    font-size: var(--text-base);
    color: var(--text-primary);
    margin-top: 0;
}

/* ===== Bounds explanation ===== */
.bounds-explanation {
    margin-top: var(--space-3);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    font-style: italic;
    line-height: 1.6;
    padding-top: var(--space-3);
    border-top: 1px solid var(--border);
}

/* ===== Video block ===== */
.video-block {
    border-radius: 10px;
    overflow: hidden;
    border: 1px solid var(--border);
    max-width: 560px;
}

.video-block video {
    width: 100%;
    display: block;
    background: #000;
}

/* ===== Submit CTA inside section ===== */
.submit-cta-section {
    margin-top: var(--space-6);
    padding-top: var(--space-6);
    border-top: 1px solid var(--border);
}

/* ===== Row notes in leaderboard ===== */
.row-note {
    display: block;
    font-size: 0.72rem;
    color: var(--text-tertiary);
    font-style: italic;
    line-height: 1.3;
    margin-top: 2px;
}

/* ===== Section headings (legacy) ===== */
.section-heading {
    font-size: var(--text-base);
    margin-top: 0;
    margin-bottom: var(--space-3);
    color: var(--text-primary);
}

/* ===== Scoring block ===== */
.scoring-block {
    margin-bottom: var(--space-8);
}

.scoring-metrics {
    list-style: none;
    padding: 0;
    margin: 0 0 var(--space-3);
}

.scoring-metrics li {
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--border);
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.scoring-metrics li:last-child {
    border-bottom: none;
}

.scoring-metrics strong {
    color: var(--text-primary);
}

.scoring-note {
    margin-top: var(--space-3);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    font-style: italic;
}

/* ===== Copy agent button ===== */
.copy-agent-btn {
    display: inline-flex;
    align-items: center;
    padding: 8px 18px;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid var(--accent);
    color: var(--accent);
    background-color: var(--accent-light);
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.copy-agent-btn:hover {
    background-color: var(--accent);
    color: #fff;
}

.copy-agent-btn:active {
    transform: scale(0.97);
}

/* ===== Show more button ===== */
.show-more-btn {
    padding: 6px 16px;
    border-radius: 6px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    background-color: var(--bg-secondary);
    cursor: pointer;
    transition: background-color 0.2s;
}

.show-more-btn:hover {
    background-color: var(--bg-tertiary);
}

/* ===== References (numbered, flat) ===== */
.references-section {
    margin-bottom: var(--space-8);
}

.references-section h3 {
    margin-top: 0;
    margin-bottom: var(--space-4);
    font-size: var(--text-lg);
}

.refs-list--numbered {
    list-style: none;
    padding: 0;
    margin: 0;
}

.refs-list--numbered li {
    padding: var(--space-2) 0;
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    border-bottom: none;
}

.refs-list--numbered a {
    color: var(--accent);
    text-decoration: none;
}

.refs-list--numbered a:hover {
    text-decoration: underline;
}

.ref-num {
    font-weight: 600;
    color: var(--text-tertiary);
    font-size: 0.8rem;
    margin-right: var(--space-2);
}

/* ===== Cite block ===== */
.cite-block {
    margin-bottom: var(--space-8);
}

.cite-block h3 {
    margin-top: 0;
    margin-bottom: var(--space-4);
    font-size: var(--text-lg);
}

.cite-bibtex {
    white-space: pre-wrap;
    font-size: 0.8rem;
    line-height: 1.7;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .problems-hero {
        padding-top: calc(var(--nav-height) + var(--space-8));
    }

    .td-mod {
        display: none;
    }

    .td-pct {
        width: 130px;
    }

    .leaderboard-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .problem-card {
        flex-direction: column;
        align-items: flex-start;
    }

    .problem-card__right {
        display: none;
    }

    .bounds-list li {
        grid-template-columns: 1fr;
        gap: var(--space-1);
    }

    .section-card {
        padding: var(--space-5) var(--space-4);
    }

    .section-card__title {
        font-size: var(--text-xl);
    }
}